Door for attenuating sound



Aug. 28, 1962 o. c. ECKEL 3,051,260

DOOR FOR ATTENUATING SOUND Filed April 6, 1960 2 Sheets-Sheet 1 6 v 6 l 1 m m Ives 1 II al 11. nfll HE I I III II I MIM MIIIIIIIII IIIII ImT I FIIIIII IIII I I MII I II II II II I.{ I! I I I I l I I I I I I "I I II II II IL, I I

Aug. 28, 1962 o. c. ECKEL 3,051,260

DOOR FOR ATTENUATING SOUND Filed April 6, 1960 2 Sheets-Sheet 2 INVENTOR.

United States Patent 3,051,260 DOOR FOR ATTENUATING SOUND Oliver C. Eckel, Carlisle, Mass. (P.O. Box 226, Cambridge 38, Mass.) Filed Apr. 6, 1960, Ser. No. 20,431 10 Claims. (Cl. 181-33) This invention relates to a sound attenuating door for use especially where sound vibrations are voluminous, as Where jet engines are tested.

One object of my invention is to provide a door with a panel assembly attached in such a manner, that it is decoupled from the main door structure, so that its motion, under excitation from sound waves, is not structurally transmitted to the remainder of the door body.

Another object is to provide said panel assembly with resilient mounting means that permits a floating movement of the panel assembly, and thus materially attenuates transmitted sound.

Still another object is to so construct my door that the degree of compliance of said panel assembly approaches the compliance of air, to thus achieve sufficient isolation to attain effective acoustic attenuation.

A further object is to provide my door with a limp septum member of high surface density (having mass without rigidity) to thereby further control transmitted sound.

A still further object is to provide an acoustical muffler for the gap between the bottom of the main door body and the threshold or floor, to thus attenuate low frequency sound that would otherwise pass through bottom sealing members in the clearance space between the door and said threshold or floor.

The foregoing and other objects which will appear as the nature of the invention is better understood, may be accomplished by a construction, combination and arrangernent of parts such as is disclosed by the drawings. The nature of the invention is such as to render it susceptible to various changes and modifications, and therefore, I am not to be limited to the construction disclosed by the drawings, nor to the particular parts described in the specification; but am entitled to all such changes therefrom as fall within the scope of my claims.

In the drawings:

FIG. 1 is an elevational view of my door, looking at the inner surface thereof.

FIG. 2 is an enlarged sectional view taken on the line 22 of FIG. 1.

FIG. 3 is an enlarged sectional view taken on the line 33 of FIG. 1.

FIG. 4 is a fragmentary, rear elevational view showing the means for sealing my door at a floor or threshold.

FIG. 5 is an enlarged, perspective view partly broken away, to show the lower portion of my door and the said sealing means at the outer and inner bodies thereof.

As illustrated, my door has an outer body portion embodying a plywood panel 11, next to which is sound absorbing material 12 such as heavy, dense mineral wool, and at opposite ends of said outer body there are wood frames 14 and 16. Screws 18 hold the latter to said panel 11. A metal cover of sheet metal 20 covers the outer face of said panel and angular portions 22 and 23 thereof continue and cover opposite ends of said panel 11 as well as opposite outer sides of said wood frames 14 and 16. Screws 24 hold said cover 20 to panel 11 and they enter frames 14 and 16.

Next to said outer body 10 is a limp septum sheet 25 of a high density material such as iubber, which may be loaded with iron or lead in small particles or in powdered form. This septum serves to reduce the sound energy transmitted through my door and also the vibration between two like materials.

3,051,260 Patented Aug. 28, 1962 ice Next to said septum is an inner body portion 26 having sound absorbing material 27 similar to said material 12, and at opposite ends of the latter are relatively thin layers 28 and 29 of a hon-bonding material such as felt or fiber glass. Also at opposite ends of said septum 25, and next to said layers 28 and 29 are stiffening or wood frames 30 and 32. Beyond the left end of said wood frame 38 is sound absorbing material 34 and laterally beyond that is a wood end frame 36. Laterally beyond said wood frame 32 is sound absorbing material 38 and laterally beyond that is a wood end frame 40. Screws 41 hold said end frames 36 and 40 respectively to wood frames 14 and 16 thus fastening the outer body 18 to inner body 26.

An acoustically floating panel 46, that is resiliently separated from other parts of the door, lies next to said sound absorbing material 27, 34 and 38 and is attached to frames 30 and 32, and overlies said frames 36 and 40. At opposite ends of said panel 46 are channelshaped resilient retainers 48 and 50 made of sponge rubber or the like which isolate said panel 46. Each said retainer 48 and 50 has, respectively a relatively long portion 48a and 56a, an end portion 48b and 50b, and a relatively short portion 480 and 500 spaced from said long portions 48:! and 50a. In the latter-mentioned spaces, reduced or cut-away ends 52 and 54 of said panel 46 extend into the spaces provided by said channel-shaped, resilient members 48 and 50 respectively.

Metal angle covers 56 and 58 cover opposite ends of said inner body 26 and extend in front of the latter, covering the outer surfaces of said retainer short portions 48c and 560 respectively. A cover 60 extends from the ends of said retainer short portions 480 and 500 across the face of said panel 46 and at opposite ends 60a and 60b it bends inwardly and enters recesses in said panel 46. Screws 61 attach said cover 60 and panel 46 to said wood frames 30 and 32. Said panel 46 with its cover 60 and said stiffening frames 30 and 32 form a panel assembly.

My door is shown attached at one end to a multi-angled frame 62 attached to a concrete wall 65. A slotted, angular stop member 63 is held by a screw 64 that screwthreadedly connects with said frame 62 and through said slotted stop member 63. A gasket 67 is between said angular frame 62 and stop member 63. Another gasket 68 is between said metal cover 60 and said stop member 63. Two gaskets 70 and 72 are between said multi-angled frame 62 and said wood frame 16, serving as a seal, thereby reducing sound transmitted through clearance space, when the door is in closed position. Said gaskets are made of soft, compliant material.

A hinge member 74 is attached to said frame as by screws 78 that are welded to frame 62 and extending through a pintle base 76. A hinge arm 80 movably extends to said outer body portion 10, being attached by screws 82 to said wood panel 11.

The lower part of said outer body 10, as shown in said FIGS. 3, 4 and 5, has a metal, U-shaped holder attached by screws 92 to said wood frame 14, and within which is a cavity filled with sound absorbing material 93. A perforated, bottom metal cover 94 extends tightly into said holder 90 and serves as the bottom for a portion of said outer body 10. Another metal, U-shaped holder 96 forms a continuation of said inner body 26, and it has a cavity filled with sound absorbing material 98 therein. A perforated, bottom metal cover 100 extends tightly into this holder 96 and serves as a bottom for a portion of said holder 96. Thus these sound absorbing materials 93 and 98 provide an acoustical mufiier in a gap between the bottom of the inner and outer body portions and the threshold or floor.

Between said holders 90 and 96 is a narrow U-shaped holder 102, into which extends resilient sealing member 104 made of rubber or t .e like, and which extends below the door main body, making rubber contact with a floor or threshold 106. A pin member shown as a screw 108 extends through a slot 103 in holder 102 and it holds said sealing member 104, said holder 102 and said holder 9% together. Between said holder M2 and the bottom of said wood frame 14 is a clearance space 1G7.

Outside said holder 96 is a narrow U-shaped holder 110 into which extends another resilient sealing member 112 made of rubber or the like, and which extends below the door main body and contacts said threshold 106. A pin member shown as a screw 114 extends through a slot 111 in holder 1110 and it holds said sealing member 112, said narrow holder Hi3 and said holder 96 together.

An angle member 116 extends from outside said retainer short portion 480 across the inner closed end of said holder 96, and attaches to frame 36 by screws 117. A straight cover member 118 of metal covers the outer portion of said angle member 116 to which it is welded, and also covers the exterior portion of said narrow holder 110. There is a clearance space 120 between said holder 110 and said angle member 116.

What I claim is:

1. A door for attenuating sound comprising an outer body portion, an inner body portion, means attachingsaid body portions together, said inner body portion embodying sound absorbing material, two frame members spaced apart intermediate opposite side extremities of said inner body and at opposite side extremities of said material, yielding material next to and interiorly of said frame members, a panel opposite and exteriorly of said frame members and sound absorbing material, means attaching said panel to said frame members, resilient retainers at opposite side extremities of said panel having openings, opposite side extremities of said panel extending into said openings, and a reslient septum sheet between said inner and outer body portions in contact with portions of said panel assembly.

2. A door for attenuating sound comprising an outer body portion, an inner body portion, means attaching said body portions together, said inner body portion embodying sound absorbing material, a panel assembly embodying two frame members spaced apart intermediate opposite side extremities of said inner body and at opposite side extremities of said material, yielding material next to and interiorly of said frame members, a panel opposite and exteriorly of said frame members and sound absorbing material, means attaching said panel to said frame members, and resilient retainers at opposite side extremities of said panel having openings, opposite side extremities of said panel extending into said openings, said inner body portion also embodying two other frame members at opposite sides of said inner body and laterally outward of the first-mentioned two frame members, portions of said resilient retainers being in contact with said two other frame members.

3. A door for attenuating sound comprising an outer body portion, an inner body portion, means attaching said body portions together, said inner body portion embodying sound absorbing material, a panel assembly embodying two frame members spaced apart intermediate opposite side extremities of said inner body and at opposite side extremities of said material, yielding material next to and interiorly of said frame members, a panel opposite and exteriorly of said frame members and sound absorbing material, means attaching said panel to said frame members, and resilient retainers at opposite side extremities of said panel having openings, opposite side extremities of said panel extending into said openings, said inner body portion also embodying two other frame members at opposite sides of said inner body and laterally outward of the first-mentioned two frame members, portions of said resilient retainers being in contact with said two other frame members, other sound absorbing materials at points adjacent opposite sides of said inner body and laterally outward of the first-mentioned two frame members.

4. A door for attenuating sound comprising an outer body portion, an inner body portion, means attaching said outer and inner body portions together, a sealing member, first means attaching said sealing member to said outer body portions, another sealing member, second means attaching said other sealing member to said inner body portion, said sealing members extending below both said body portions, each said body portion embodying sound absorbing material laterally opposite said sealing members, third means retaining said sound absorbing materials, said first means and second means each having a slot therein, and pin members attaching said sealing members to said first means and second means and attached to said third means, said pin members extending through said slots whereby said sealing members may be moved to a predetermined position.

5. A door for attenuating sound comprising an outer body portion, an inner body portion, means attaching said body portions together, said inner body portion embodying sound absorbing material, two frame members spaced apart intermediate opposite side extremities of said inner body and at opposite side extremities of said material, yielding material next to and interiorly of said frame members, a panel opposite and exteriorly of said frame members and sound absorbing material, means attaching said panel to said frame members, resilient retainers at opposite side extremities of said panel having openings, opposite side extremities of said panel extending into said openings, a resilient septum sheet between said inner and outer body portions in contact with portions of said panel, a sealing member, means attaching said sealing member to said outer body portion, another sealing member, means attaching said other sealing member to said inner body portion, said sealing members extending below both said body portions, each said body portion embodying sound absorbing material laterally opposite said sealing members, and means retaining said sound absorbing materials.

6. A door for attenuating sound comprising an outer body portion embodying a first U-shaped holder, an inner body portion embodying a second U-shaped holder, means attaching said outer and inner body portions together, a sealing member, means attaching the latter to said first U-shaped holder, another sealing member, means attaching the latter to said second U-shaped holder, said sealing members extending below both said body portions, each said body portion embodying flexible, sound absorbing material laterally opposite said sealing members and in said U-shaped holders, and means retaining said sound absorbing materials in said holders.

7. A door for attenuating sound comprising an outer body portion embodying a first U-shaped holder, an inner body portion embodying a second U-shaped holder, means attaching said outer and inner body portions together, a third U-shaped holder, a sealing member extending into said latter holder, a pin member attaching said third holder and said sealing member to said first U-shaped holder, a fourth U-shaped holder, another sealing member extending into said fourth holder, a pin member attaching said fourth holder to said second U- shaped holder, said sealing members extending below both said body portions, each said body portion embodying flexible, sound absorbing material laterally opposite said sealing members and in said first and second U- shaped holders, and means retaining said sound absorbing materials in said holders, said third and fourth holders each embodying a slot therein whereby the positions of said pin members in said slots may be adjusted to thereby adjust the positions of said sealing members relative to said body portions.

8. A door for attenuating sound comprising an outer body portion, an inner body portion, both said body portions embodying sound absorbing material, and a limp septum sheet between said body portions, each of said body portions embodying a firm panel exteriorly of said sound absorbing materials of both said body portions, said inner body portion embodying channel-shaped, resilient retainers at opposite side extremities of said inner body portion panel having openings, the opposite side extremities of said latter panel extending into said openings.

9. A door for attenuating sound comprising an outer body portion, an inner body portion, narrower than said outer body portion, said outer body portion overlapping said inner body portion at opposite sides, both said body portions embodying sound absorbing material, and a limp septum sheet of high density rubber material between said body portions and said sound absorbing materials and adjacent the latter extending substantially the full width and height of said inner body portion, each of said body portions embodying a firm panel ex-teriorly of said sound absorbing materials of both said body portions, said inner body portion embodying channel-shaped, resilient retainers at opposite side extremities of said inner body portion panel and having openings, the opposite side extremities of said latter panel extending into said openlugs.

10. A door for attenuating sound comprising an outer body portion, an inner body portion, means attaching said outer and inner body portions together, a sealing member, means attaching said sealing member to said outer body portion, another sealing member, means attaching said other sealing member to said inner body portion, said sealing members extending below and outside both said body portions, each said body portion embodying sound absorbing material laterally opposite said sealing members, and means embodying a cover retaining said material in each said body portion, each said cover having perforations therein.

References Cited in the file of this patent UNITED STATES PATENTS 1,963,819 Yates June 19, 1934 2,078,207 Page et a1 Apr. 20, 1937 2,079,878 Sabine May 11, 1937 2,111,326 Norris Mar. 15', 1938 2,178,729 Shields Nov. 7, 1939 2,240,014 Peik Apr. 29, 1941 2,350,513 Leadbetter June 6, 1944 2,556,884 Muller June 12, 1951 2,880,471 Von Munchhausen Apr. 7, 1959 FOREIGN PATENTS 574,466 Great Britain Jan. 7, 1946 OTHER REFERENCES Fab- 

